initial

core.clj

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+(ns meh.schedule
+  (:refer-clojure :exclude [==])
+  (:require [clojure.core.logic :as logic :refer [run* run == fresh conde membero]]
+            [clojure.core.logic.fd :as fd]
+            [clj-http.client :as client]
+            [clojure.string :as str]
+            [hickory.core :as html]
+            [hickory.select :as sel]))
+
+(defn time->num [timestamp]
+  (let [[h m] (str/split timestamp #":")
+        pm? (str/ends-with? m "PM")
+        h (parse-long h)
+        h (if (= h 12) 0 h)
+        h (if pm? (+ h 12) h)
+        m (parse-long (str/replace m #"(A|P)M" ""))]
+    (+ (* h 100) m)))
+
+(def base-url (System/getenv "TIMETABLE_URL"))
+
+(def get-timetable
+  (memoize
+   (fn [& {:keys [campus-code term subject number] :or {term "202501" campus-code 0}}]
+     (let [params {:CAMPUS campus-code
+                   :TERMYEAR term
+                   :SUBJ_CODE subject
+                   :CRSE_NUMBER number
+                   :open_only ""
+                   :CORE_CODE "AR%"
+                   :PRINT_FRIEND "Y"
+                   :history "N"
+                   :disp_comments_in "Y"}
+           resp (client/post base-url
+                             {:form-params params})
+           page (-> resp :body html/parse html/as-hickory)
+           rows (drop 1 (sel/select (sel/tag :tr) page))]
+       (->> rows
+            (map :content)
+            (map (partial map
+                          #(or (get-in % [:content 2 :content 0])
+                               (get-in % [:content 1 :content 0])
+                               (get-in % [:content 0 :content 0])
+                               (get-in % [:content 0]))))
+            (map (partial filter string?))
+            (filter (fn [[crn & _]] (parse-long crn)))
+            (map (fn [[crn _ _ modality capacity _ days start end room _]]
+                   {:crn (parse-long crn)
+                    :subject subject
+                    :number number
+                    :modality (if (= modality "Face-to-Face Instruction") :in-person :online)
+                    :days (mapv (comp keyword str/lower-case) (str/split days #"\s+"))
+                    :start (time->num start)
+                    :end (time->num end)
+                    :room room})))))))
+
+(defn classo [class days start end]
+  (logic/all
+   ; the clojure way: extra keys are *not* an error
+   (logic/featurec class {:days days :start start :end end})
+   (fd/< start end)))
+
+(defn non-overlappingo [a b]
+  (fresh [daysa starta enda daysb startb endb]
+    (classo a daysa starta enda)
+    (classo b daysb startb endb)
+
+    (conde
+     [(fresh [days]
+        (logic/appendo daysa daysb days)
+        (logic/distincto days))]
+     [(fd/< enda startb)]
+     [(fd/< endb starta)])))
+
+(defn all-non-overlappingo [classes]
+  (logic/and*
+   (for [a classes
+         b classes]
+     (conde [(== a b)]
+            [(non-overlappingo a b)]))))
+
+(defn scheduleo [sch classes]
+  (if (first classes)
+    (let [[[subject number] & classes] classes]
+      (fresh [class sch']
+        (membero class (get-timetable :subject subject :number number))
+        (logic/conjo sch' class sch)
+        (scheduleo sch' classes)))
+    (all-non-overlappingo sch)))

deps.edn

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+{:deps
+ {org.clojure/clojure {:mvn/version "1.12.0"}
+  org.clojure/core.logic {:mvn/version "1.1.0"}
+  clj-http/clj-http {:mvn/version "3.13.0"}
+  org.clj-commons/hickory {:mvn/version "0.7.7"}}}